Iranian Journal of Virology
Volume:4 Issue: 1, 2010

The hepatitis C virus (HCV) F protein is a recently described, frameshift product of HCV core encoding sequence. Its function and antigenic properties are unknown. In order to assess the presence of antibodies specific for F protein we characterized specific anti-F antibodies in patients with chronic HCV infection. The F protein was cloned from the HCV genome. The recombinant protein was expressed in Escherichia coli and purified by immunoaffinity chromatography. An enzyme-linked immunosorbent assay was developed using the purified recombinant HCV F protein. Serum samples were collected from 72 patients with chronic HCV infection and from 30 healthy controls. Eighty-two percent of chronic HCV patients had evidence of anti-F antibodies. 59 samples out of the 72 HCV infected patients exhibited a positive anti-F reaction, showing significant difference from the controls with no HCV infection (P < 0.01). Based on these findings, HCV F protein elicits a specific antibody response, so frameshift could occur in the core-coding sequence in HCV genotype 1a in Iranian patients. As the first report, the prevalence of anti-F antibodies in chronic hepatitis C in Iran is of the order of 82%.

Virus-Induced Gene Silencing (VIGS) is a virus vector technology that exploits antiviral defense mechanism. By infecting plants with recombinant viruses containing host genes inserted in the viral genome, VIGS achieves the RNA silencing process. The purpose of this study was to investigate the possibility of tomato (Lycopersicon esculentum Mill.) and tobacco (Nicotiana benthamiana) phytoene desaturase (PDS) gene silencing, using VIGS technique by VIGS vector containing tomato PDS. PDS gene encodes one of the important enzymes in the carotenoid biosynthesis pathway. In this method Tobacco rattle tobravirus (TRV) vectors including pTRV1، pTRV2 and pTRV2PDS were used. The pTRV2PDS vector carried inserts derived from tomato PDS gene. Vectors were transformed into Escherichia coli strain DH5α. Agrobacterium tumefaciens strain GV3101 cells were transformed by the vectors containing specific genes. Colony PCR with specific primers proved the presence of the PDS and RNA-dependent RNA polymerase genes in selected agrobacterium random colonies. Agrobactrium containing pTRV1، pTRV2 and pTRV2PDS was inoculated into induction media culture. Finally, acetosyringone was added to pTRV1 culture and then pTRV1 and pTRV2PDS cultures mixed in a 1:1 ratio. Mixed culture was infiltrated into the test plant seedlings using 1ml needless syringe. Results showed the gene silencing in the form of photobleaching and mosaic occurred in tomato and tobacco plant leaves, respectively. However, plant infiltration with pTRV1 and pTRV2 (without PDS gene as control) mixed culture did not show any photobleaching.

Influenza A viruses are important pathogens for humans especially in pandemic episodes. Two adamantane derivates, amantadine and rimantadine, are used for prophylaxis and treatment of influenza A virus infections. However, single amino acid substitutions in the M2 transmembrane domain which lead to amantadine resistance of these viruses occur at residues 26, 27, 30, 31 or 34. Rates of resistant viruses have been increasing globally. In this report, 21 specimens of seasonal H1N1 and pandemic influenza A viruses which grew on MDCK cell line were studied for detection of amantadine resistant viruses. After RT-PCR M2 gene of samples were sequenced. In addition, as confirmatory assay, amplification of pandemic influenza A viruses on amantadine treated MDCK cell line and evaluation of TCID50 assay, were accomplished. All seasonal influenza A viruses were amantadine sensitive but none of the 2009 pandemic influenza A viruses where us none of the 2009 pandemic influenza A virus were sensitive. Considering emergence of new influenza A virus variant, and resistance to amantadine, it is noteworthy that application of amantadine in new variant A/H1N1 influenza viruses might not be effective.

The causal agents of viral lettuce big vein disease are two viruse, Lettuce big vein associated virus (Varicosavirus) and Mirafiori lettuce virus (Ophiovirus). These viruses have coat proteins of similar size but have different morphologies and serologically unrelated.The purpose of this study was to distinguish and detect LBVaV and MiLV in lettuce fields in Tehran Province. Patients and A total 344 samples with mosaic and big vein, head stunt, leaf deformation and motteling symptoms were collected from lettuce fields in Tehran Province.Using DAS – ELISA and specific antiserum for MiLV (DSMZ, AS-0798) and RT-PCR for LBVaV. Positive samples in ELISA and RT-PCR were inoculated on index plants,including Chenopodium quinoa, Chenopodium amaranticolor, Lactuca sativa and Nicotiana occidentalis p1. The results of ELISA and RT-PCR about MiLV showed that, virus is transmitted on C.quinoa and produced chlorotic local lesion but about LBVaV, RT-PCR showed that C.quinoa and C.amaranticolor were infected and the virus caused chlorotic local lesion. Extraction of total RNA with three methods using RNAWIZ buffer, Guanidium isothiosianat buffer and Qiagen kit showed that exteraction with RNeasy plant minikit (Qiagen company) is better for RT-PCR. RT-PCR with LBVaV and MiLV specific primer pairs (were designed with Navaro et al. 2004) were performed and the fragment length were amplified for LBVaV and MiLV respectively 296bp and 469bp. The sequence nucleotides of CP of LBVaV was determined and had high similarity with other isolates in gene bank. This is the first report of occurrence of these viral diseases in lettuce in Iran (Tehran Province).

Virus-like particles (VLPs) have been suggested to be a promising recombinant vaccine approach. Several studies have reported that the influenza VLPs produced in insect cells is an effective vaccine candidate. Due to crucial role of matrix M1 protein in assembly and budding of Influenza particles, in all VLPs structures, M1 protein have been considered as a main component. M1 open reading frame (759 bp) from human influenza virus A /New Caledonia 20/1999/ (H1N1) was amplified by RT-PCR. The amplicone was cloned into pFastBac1 donor plasmid through KpnI/XhoI sites. After verification of clone by restriction analysis, it was subjected to automated sequencing. The M1 recombinant bacmid was subsequently generated and verified by PCR using M1 specific and M13 universal primers. results showed that a recombinant baculovirus containing correct and inframe sequence of Influenza M1 gene under control of polyhedrin promoter has been constructed. The above-mentioned M1 recombinant baculovirus can be used with other individual recombinant baculoviruses expressing HA and NA genes to produce influenza VLPs in insect cell line.